1. Technical Field
The present disclosure relates to an image acquisition device, an image forming system, and an image forming method.
2. Description of the Related Art
Conventionally, an optical microscope is used to observe a microstructure of a living tissue or the like. Light transmitted through or reflected from an observation object is used in the optical microscope. An observer observes an image enlarged through a lens. There is also known a digital microscope that photographs the image enlarged through a lens and displays the image on a display. The use of the digital microscope enables simultaneous observation by a plurality of persons or remote observation.
Nowadays a technology of observing the microstructure by a CIS (Contact Image Sensing) scheme attracts attention. For the CIS scheme, the observation object is disposed in proximity to an imaging surface of an image sensor. A two-dimensional image sensor in which many photoelectric converters are two-dimensionally arrayed in the imaging surface is generally used as the image sensor. Typically the photoelectric converter is a photodiode formed in a semiconductor layer or a semiconductor substrate, and the photoelectric converter generates a charge by receiving incident light.
The image captured with the image sensor is defined by many pixels. Each pixel is divided by a unit region including one photoelectric converter. Accordingly, resolving power (resolution) of the two-dimensional image sensor usually depends on an array pitch of the photoelectric converter on the imaging surface. Hereinafter, sometimes the resolving power depending on the array pitch of the photoelectric converter is referred to as “intrinsic resolving power” of the image sensor. Because the array pitch of each photoelectric converter is shortened up to a degree of a wavelength of visible light, it is difficult to further improve the intrinsic resolving power.
There is proposed a technology of resolving power exceeding the intrinsic resolving power of the image sensor. PTL 1 discloses a technology of forming a subject image using a plurality of images obtained by a shift of an image formation position of a subject.